/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jasper.compiler;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

import org.apache.jasper.JspCompilationContext;

/**
 * Class providing details about a javac compilation error.
 * 
 * @author Jan Luehe
 * @author Kin-man Chung
 */
public class JavacErrorDetail {

	private String javaFileName;
	private int javaLineNum;
	private String jspFileName;
	private int jspBeginLineNum;
	private StringBuffer errMsg;
	private String jspExtract = null;

	/**
	 * Constructor.
	 * 
	 * @param javaFileName
	 *            The name of the Java file in which the compilation error
	 *            occurred
	 * @param javaLineNum
	 *            The compilation error line number
	 * @param errMsg
	 *            The compilation error message
	 */
	public JavacErrorDetail(String javaFileName, int javaLineNum,
			StringBuffer errMsg) {

		this.javaFileName = javaFileName;
		this.javaLineNum = javaLineNum;
		this.errMsg = errMsg;
		this.jspBeginLineNum = -1;
	}

	/**
	 * Constructor.
	 * 
	 * @param javaFileName
	 *            The name of the Java file in which the compilation error
	 *            occurred
	 * @param javaLineNum
	 *            The compilation error line number
	 * @param jspFileName
	 *            The name of the JSP file from which the Java source file was
	 *            generated
	 * @param jspBeginLineNum
	 *            The start line number of the JSP element responsible for the
	 *            compilation error
	 * @param errMsg
	 *            The compilation error message
	 */
	public JavacErrorDetail(String javaFileName, int javaLineNum,
			String jspFileName, int jspBeginLineNum, StringBuffer errMsg) {

		this(javaFileName, javaLineNum, jspFileName, jspBeginLineNum, errMsg,
				null);
	}

	public JavacErrorDetail(String javaFileName, int javaLineNum,
			String jspFileName, int jspBeginLineNum, StringBuffer errMsg,
			JspCompilationContext ctxt) {

		this(javaFileName, javaLineNum, errMsg);
		this.jspFileName = jspFileName;
		this.jspBeginLineNum = jspBeginLineNum;

		if (jspBeginLineNum > 0 && ctxt != null) {
			InputStream is = null;
			FileInputStream fis = null;

			try {
				// Read both files in, so we can inspect them
				is = ctxt.getResourceAsStream(jspFileName);
				String[] jspLines = readFile(is);

				fis = new FileInputStream(ctxt.getServletJavaFileName());
				String[] javaLines = readFile(fis);

				// If the line contains the opening of a multi-line scriptlet
				// block, then the JSP line number we got back is probably
				// faulty. Scan forward to match the java line...
				if (jspLines[jspBeginLineNum - 1].lastIndexOf("<%") > jspLines[jspBeginLineNum - 1]
						.lastIndexOf("%>")) {
					String javaLine = javaLines[javaLineNum - 1].trim();

					for (int i = jspBeginLineNum - 1; i < jspLines.length; i++) {
						if (jspLines[i].indexOf(javaLine) != -1) {
							// Update jsp line number
							this.jspBeginLineNum = i + 1;
							break;
						}
					}
				}

				// copy out a fragment of JSP to display to the user
				StringBuffer fragment = new StringBuffer(1024);
				int startIndex = Math.max(0, this.jspBeginLineNum - 1 - 3);
				int endIndex = Math.min(jspLines.length - 1,
						this.jspBeginLineNum - 1 + 3);

				for (int i = startIndex; i <= endIndex; ++i) {
					fragment.append(i + 1);
					fragment.append(": ");
					fragment.append(jspLines[i]);
					fragment.append("\n");
				}
				jspExtract = fragment.toString();

			} catch (IOException ioe) {
				// Can't read files - ignore
			} finally {
				if (is != null) {
					try {
						is.close();
					} catch (IOException ioe) {
						// Ignore
					}
				}
				if (fis != null) {
					try {
						fis.close();
					} catch (IOException ioe) {
						// Ignore
					}
				}
			}
		}
	}

	/**
	 * Gets the name of the Java source file in which the compilation error
	 * occurred.
	 * 
	 * @return Java source file name
	 */
	public String getJavaFileName() {
		return this.javaFileName;
	}

	/**
	 * Gets the compilation error line number.
	 * 
	 * @return Compilation error line number
	 */
	public int getJavaLineNumber() {
		return this.javaLineNum;
	}

	/**
	 * Gets the name of the JSP file from which the Java source file was
	 * generated.
	 * 
	 * @return JSP file from which the Java source file was generated.
	 */
	public String getJspFileName() {
		return this.jspFileName;
	}

	/**
	 * Gets the start line number (in the JSP file) of the JSP element
	 * responsible for the compilation error.
	 * 
	 * @return Start line number of the JSP element responsible for the
	 *         compilation error
	 */
	public int getJspBeginLineNumber() {
		return this.jspBeginLineNum;
	}

	/**
	 * Gets the compilation error message.
	 * 
	 * @return Compilation error message
	 */
	public String getErrorMessage() {
		return this.errMsg.toString();
	}

	/**
	 * Gets the extract of the JSP that corresponds to this message.
	 * 
	 * @return Extract of JSP where error occurred
	 */
	public String getJspExtract() {
		return this.jspExtract;
	}

	/**
	 * Reads a text file from an input stream into a String[]. Used to read in
	 * the JSP and generated Java file when generating error messages.
	 */
	private String[] readFile(InputStream s) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(s));
		List lines = new ArrayList();
		String line;

		while ((line = reader.readLine()) != null) {
			lines.add(line);
		}

		return (String[]) lines.toArray(new String[lines.size()]);
	}
}
